Downhole operations, including well production or completion, particularly for oil and natural gas wells, utilize components and tools, particularly rotatable components and tools, which must maintain a high abrasion resistance and a low coefficient of sliding friction under extreme conditions, such as, high temperatures and high pressures for their efficient operation. These include many types of rotatable rotors, shafts, bushings, bearings, sleeves and the like. The high temperatures can be elevated further by heat generated by the components and tools themselves. The materials used to fabricate these downhole components and tools are carefully selected to provide the properties described under these extreme operating conditions.
Additionally, in some applications, these components and tools are designed to have limited service lives and are configured to be removed or disposed of in order to recover the original size of the fluid pathway for use, including hydrocarbon production, CO2 sequestration, etc. In order to eliminate the need for milling or drilling operations for removal or disposal, the removal of components and tools formed of a nanomatrix powder metal compact by rapid, controlled dissolution has been described in the following co-pending patent applications: U.S. patent application Ser. Nos. 12,633,682; 12/633,686; 12/633,688; 12/633,678; 12/633,683; 12/633,662; 12/633,677; and Ser. No. 12/633,668 that were all filed on Dec. 8, 2009; Ser. No. 12/847,594 that was filed on Jul. 30, 2010 and Ser. No. 12/913,321 filed on the same date as this application, which are assigned to the same assignee as this application, Baker Hughes Incorporated of Houston, Tex.; and which are incorporated herein by reference in their entirety.
In order to maintain a high abrasion resistance, a low coefficient of sliding friction or a high thermal conductivity, or a combination of these properties, these downhole components and tools frequently employ surface coatings, internal layers or other features to provide these characteristics. These features must also be compatible with the overall material systems used to manufacture these components and tools, such as, for example, material systems comprising nanomatrix powder metal compacts.
Therefore, the development of materials having the desired combination of high abrasion resistance, low coefficient of sliding friction, or high thermal conductivity, or a combination of these properties, for use in downhole components and tools, particularly those that include nanomatrix powder metal compacts, is very desirable.